The LS diff. was replaced several years ago when parts of the "clutches" were found laying in the housing during a routine lube change. The Diff. appeared to be working normally and made no noise to indicate the failure.
Now, Around town / short trips, no issues. After 5 hours of highway running it gets noisy when turning for a bit, then its fine. I'm guessing that the lube is not holding up to prolonged use / heat.
I'm going to change the gear lube in the morning to Mobil1 LS 75w-90. They claim that no LS additive is required. Should I put some in anyway?
Ski